So…what is this obvious measure that you're referring to?  I must be missing something….From your question I wonder if the United States could have been held together with some sort of Constitutional Amendment allowing the slave states to maintain their slavery.  Would this have prevented war by keeping the Union in tact?  Or would this still not have been enough to keep the country together and prevent war?

Henry Clay staved off the war for decades, but it was inevitable as slavery invoked a peculiar paranoia that prompted the planters to perceive a perpetual conspiracy being prattled about by abolitionists and Northern politicians who played on the passions of the people against them.  So basically Southerners created the war for themselves out of unfounded fears of federal plans to finish off the expansion of slavery for good…..plans that were never really set in motion.

My professor at Louisville said the South commited “state suicide.”

From all I have read, I get the impression the south did not give an inch on anything. Whats your impression?

That's basically right.  The South refused to compromise as the Fire-Eaters (Secessionists)overwhelmed the political debate leading up to the war.  They fed propaganda to the general populace of the Confederate States that a Lincoln led government was prepared to destroy slavery when in fact Lincoln harbored no such plans or desires.  Had the more reasonable and level-headed leaders of the South managed to get their message across…namely that Lincoln was a man that a deal could be cut, perhaps the South could have avoided war.  One could say that Lincoln dropped the ball by not being more vocal in reassuring the Southern planters of what his true intentions were.  I don't fault Lincoln on this because I really don't think his Public Relations Team had much of a chance to dispel the fears that spread throughout the South.  Lincoln didn't have a mass media apparatus to  effectively get his message out in the forceful and compeling manner he needed.  For some reason fear travels faster than reason. 🙁

In my opinion, I dont think there was any avoiding it (especially after he was elected), maybe Lincoln could have set something up that would have let slavery play it’s course and died at some point down the road. But the war had been coming for decades, and not just over slavery.

I’m reminded of the Confederates who took up and moved to Brazil to carry on their way of life.  There may be another thread on this forum about the group, which I believe numbered in the thousands.  For them, slavery eventually faded away.